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1

Computational and Experimental Investigation of Inert Gas Flow Field in Direct Metal Laser Melting Printer Build Chambe

Czekałowski Paweł, Stryczniewicz Wit, Żuk Paweł, Panna Krzysztof, Borkowski Paweł, Bujak Michał, Iglewski Tomasz

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 6

378--387

EN

Additive manufacturing methods are becoming more and more popular in today’s production market. These methods became a useful and flexible alternative to traditional manufacturing approach. One of the most popular methods in this family is Direct Metal Laser Melting. It can achieve high quality prints, however, numerous parameters need to be established, to achieve a good quality product. One of the aspects of printing process is inert gas flow. The goal of presented study is to quantitatively assess inert gas flow field using both experimental and numerical methods. Flow field parameters have been measured with anemometry and Particle Image Velocimetry. Additionally Computational Fluid Dynamics tools were used to investigate flow phenomena occurring inside the build chamber. PIV measurements give good insight into the flow field, but they are costly and require significant time for preparation. For this reason, CFD analysis is widely used as a design tool, giving reasonable turnaround time. In addition, every design tool to be reliable need to be validated against test data. In this study the team was able to collect both experimental and numerical data and finally conduct the validation. Work allowed to determine the most suitable approach for predictions in given problem. Different turbulence models have been tested. Simulation results were validated against collected experimental data.

2

Theoretical description of PIV measurement errors

Cameron Stuart Murray

Acta Geophysica

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2022

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Vol. 70, no 5

2379--2387

EN

Expressions for particle image velocimetry (PIV) mean error and error variance are derived for iterative deformation method algorithms. The analytical expressions explicitly account for the role of in- and out-of-plane displacements, displacement gradients, particle image diameter, fill factor of the imaging sensor, image noise, light sheet intensity distribution, seeding particle concentration, the interpolation function used to deform PIV images, and the interrogation window size and weighting window. The newly derived analytical expressions show good agreement with errors estimated using synthetic image sets.

3

Validation of CFD predictions for flow over a full-scale formula student vehicle using PIV in real conditions

Wengrzyn Oskar

Journal of TransLogistics

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2021

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Vol. 7, nr 1

129--146

EN

Computational Fluid Dynamics (CFD) predictions are becoming an industry standard. They allow for making accurate predictions of complex problems without requiring extensive real-world testing, as well as saving time and money. However, it has been proven many times that the classic Reynolds-averaged Navier – Stokes (RANS) approach has its flaws and fails to provide highly accurate predictions. Even though CFD only approaches a physical solution, which can be reached only in very specific applications, it usually provides enough precision for engineering purposes. To reach a convergence with real-world physics, plenty of factors must be taken into consideration like mesh, boundary conditions, and turbulence models. In order to obtain a CFD simulation that accurately represents real physics, some kind of real-world validation must take place. For aerodynamics, it is usually done in wind tunnels, which are expensive to run but provide controllable conditions to match those specified in CFD. One of the many methods used to validate the calculations is Particle Image Velocimetry (PIV). This study tries to validate CFD of a Formula Student car using PIV, but in real-world conditions, without wind tunnel. The compact size of equipment required for PIV testing and flexibility of CFD boundary conditions allow for that.

PL

Prognozy obliczeniowej dynamiki płynów (CFD) stają się standardem branżowym. Pozwalają na dokładne przewidywanie złożonych problemów bez konieczności przeprowadzania rozległych testów w warunkach rzeczywistych, oszczędzając czas i pieniądze. Jednak wiele razy zostało udowodnione, że klasyczne podejście Reynoldsa uśrednione Navier-Stokes (RANS) ma swoje wady i nie zapewnia bardzo dokładnych prognoz. Mimo że CFD zbliża się tylko do rozwiązania fizycznego i może osiągnąć je tylko w bardzo specyficznych zastosowaniach, do celów inżynieryjnych zwykle zapewnia wystarczającą precyzję. Aby osiągnąć zbieżność z rzeczywistą fizyką, należy wziąć pod uwagę wiele czynników, takich jak siatka, warunki brzegowe i modele turbulencji. Aby mieć symulację CFD, która dokładnie odzwierciedla rzeczywistą fizykę, musi nastąpić pewnego rodzaju walidacja w prawdziwym świecie. Zwykle odbywa się to w tunelach aerodynamicznych, jeśli mówimy o aerodynamice, które są drogie w eksploatacji, ale zapewniają kontrolowane warunki, aby dopasować się do tych określonych w CFD. Jedną z wielu metod stosowanych do walidacji obliczeń jest Velocymetria obrazu cząstek (PIV). To badanie próbuje zweryfikować CFD samochodu Formula Student przy użyciu PIV, ale w rzeczywistych warunkach, bez tunelu aerodynamicznego. Umożliwiają to kompaktowe rozmiary sprzętu wymaganego do testów PIV i elastyczność warunków brzegowych CFD.

4

Image velocimetry and statistical analysis of a mesh-coupled axial blade distributor for mass transfer in a swirling bed

Javed Muhammad Asif, Shukrullah Shazia, Naz Muhammad Yasin, Sarfraz Raja Adil

Journal of Theoretical and Applied Mechanics

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2020

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Vol. 58 nr 3

779--790

EN

A mesh-coupled axial blade distributor was tested for fluidization of particles in a swirling fluidized bed. The bed velocity was estimated experimentally using a high-speed imaging device and MATLAB supported particle image velocimetry (PIV). The bed velocity was also predicted statistically with a response surface analysis method. During statistical analysis, the confidence interval of bed velocity remained between 0.49485 and 0.49998. The bed velocity was measured about 0.49741m/s and 0.538m/s through experimental and statistical methods, respectively. The experimental and statistical analysis revealed similar bed weights and superficial velocities with a slight difference of 6.4◦ in blade angles.

5

Algorytmy do analizy składowych wektora prędkości

Gawor Marek, Sobczyk Jacek, Wodziak Waldemar

Prace Instytutu Mechaniki Górotworu PAN

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2019

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T. 21, nr 1-4

39--47

PL

W artykule przedstawiono algorytmy komputerowe zaprojektowane w celu analizy składowych płaskiego pola prędkości. Informacje o składowych wektora prędkości pochodzą z programu Dantec Dynamic Studio lub programu powstałego w Instytucie. Analizowane są wszystkie pliki z wybranego katalogu. Programy te generują płaskie pola prędkości wyznaczane przy pomocy anemometrii cyfrowej (Particle Image Velocimetry – PIV). W programie możemy analizować składowe wektora prędkości wzdłuż linie poziomej i pionowej. Możemy zapisać pliki w celu narysowania trójwymiarowego pola wybranej składowej wektora prędkości lub zmiany składowych w czasie. Istnieje możliwość wyznaczenia sumy, wartości średniej, odchylenia standardowego, czy rotacji wektora prędkości.

EN

Algorithms used to analyze velocity of vector components are presented in the paper. Information about velocity components come from Dantec Dynamic Studio Program or program designed by the authors. All of the files from the selected catalogue are analyzed. As a result 2D velocity fields are generated from the PIV data. The authored computer program allows to analyze velocity vector components along horizontal and vertical lines. Files saved are used to draw a three dimensional velocity fields or to visualize variations of the components of velocity vectors in time. Statistical parameters such as: sum, mean, standard deviation or rotation of the velocity vector are routinely computed.

6

Study of flow behaviour in a three products hydrocyclone screen: numerical simulation and experimental validation

Wang Chuanzhen, Chen Jianzhong, Shen Lijuan, Ge Linhan

Physicochemical Problems of Mineral Processing

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2019

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Vol. 55, iss. 4

879--895

EN

A novel three products hydrocyclone screen (TPHS) has been successfully developed; it consists of a cylindrical screen embedded in a conventional hydrocyclone (CH). In the new liquid cyclone, the combination of centrifugal classification and screening was employed for particle separation based on size. The aim of this study is to investigate the flow behaviour in TPHS using numerical simulation and experimental validation. A computational fluid dynamics simulation with a 4.35 million grid scheme and linear pressure–strain RSM generated the economic and grid-independence solution, which agreed well with the experiments of particle image velocimetry and water split. The velocity vector profile reveals that TPHS represented similar flow patterns to CH, wherein in addition to the outer downward swirl flow, inner upward swirl flow, central down-flow, second circulatory flow, and mantle, a particular fluid flow named screen underflow was created in TPHS owing to the presence of a cylindrical screen. The velocity distribution demonstrates that in TPHS, relative to CH, with the increase in radius, the lower tangential and higher radial velocity first increased to a peak and subsequently decreased, while the axial velocity primarily reduced to zero, increased in the opposite direction, and finally decreased rapidly to zero again. In addition, a disadvantageous flow, namely, screen backflow, was generated in TPHS, wherein the farther away the flow is from the feed inlet, the earlier this flow behaviour occurred. However, the rational scheme of aperture size and screen length can completely remove the screen backflow in TPHS.

7

Laboratory study of suspended sediment dynamics over a mildly sloping sandy seabed

Stachurska Barbara, Staroszczyk Ryszard

Oceanologia

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2019

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No. 61 (3)

350--367

EN

This paper presents the results of laboratory measurements of suspended sediment movement induced by regular non-linear water waves propagating over a mildly sloping sandy seabed covered with ripples. The measurements conducted in a water flume were carried out by applying the technique of particle image velocimetry (PIV). The aim of those experiments was to investigate near-bed velocities of sediment particles under controlled surface wave conditions. In particular, horizontal and vertical profiles of sand grain velocities were measured, and some comparisons between the measured and theoretically-predicted quantities were carried out. A number of selected wave cases were examined, for which the Ursell number ranged from 18 to 39, and the sediment grain mobility numbers varied between 12 and 26. For these flow conditions, the near-bed layer of intense sediment grain movements had a thickness of about 2-3 ripple heights. The maximum horizontal sediment velocities measured over ripple crests were about twice as large as those over ripple troughs. Vertical sediment velocities above ripple crests and troughs were similar, amounting to about 1/4 to 1/3 of horizontal velocities over ripple crests. The detailed quantitative results obtained in the flume can help validate other experimental techniques and can be useful in testing numerical models for simulating surface wave-induced sediment dynamics.

8

Wyznaczanie pola wektorów prędkości strumienia powietrza wypływającego z nawiewnika

Szmelter Aleksandra

Materiały Budowlane

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2019

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nr 2

34--35

PL

W artykule zaprezentowano badanie doświadczalne z dziedziny wentylacji, przeprowadzone w Małopolskim Laboratorium Budownictwa Energooszczędnego z wykorzystaniem metody Stereo Particle Image Velocimetry (Stereo PIV). Opisano wyposażenie laboratorium badawczego obejmujące system PIV, a także metodę. Zaprezentowano wstępne wyniki doświadczeń ze strumieniami powietrza wypływającego z nawiewnej kratki wentylacyjnej, stosowanej w typowym budownictwie mieszkaniowym.

EN

The article presents an experimental study in the field of ventilation, carried out in the Malopolska Laboratory of Energy Efficient Buildings. Stereo Particle Image Velocimetry (Stereo PIV) method was used in the experiment. The specification of the equipment of the research laboratory including the PIV system was included, as well as a brief description of the method. Preliminary results of the tests of the air stream flowing out of the ventilation grille used in typical housing construction have been presented.

9

Przykładowe realizacje pomiarów płaskich pól prędkości wiatru (wersja 2D) w inżynierii wiatrowej

Bosak Grzegorz

Inżynieria i Budownictwo

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2019

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R. 75, nr 3

139--143

PL

Przedstawiono wybrane prace pomiarowe pól prędkości wiatru wykonane za pomocą systemu PIV (Particle Image Velocimetry) w Laboratorium Inżynierii Wiatrowej Politechniki Krakowskiej. Podano zasady pomiaru, scharakteryzowano główne elementy systemu oraz opisano podstawowe zalety i trudności realizacji pomiarów taką techniką. Określono podstawowe obszary badawcze inżynierii wiatrowej, w których pomiary tą techniką mogą mieć praktyczne zastosowania.

EN

The article presents chosen measurement works of wind velocity fields by means of a PIV system (Particle Image Velocimetry) fulfilled in Wind Engineering Laboratory of Cracow University of Technology. The principles of PIV system measurement are presented, the main elements of the system are characterised and fundamental advantages and difficulties of a measurement execution by this type of a technique are described. The basic research fields of wind engineering are defined, in which the measurements of this technique could have practical applications.

10

Investigation of the sedimentation process using flow visualization methods

Suchecki Witold

Chemical and Process Engineering

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2019

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Vol. 40, nr 2

223–-233

EN

The aim of the paper was to develop determination methods of sedimentation characteristics using PIV image anemometry and suspension image analysis. Two methods of the investigation of sed- imentation process based on visualization techniques were developed. In the first one, using PIV method, vector fields of the velocity of settling particles are determined and then average particle velocities are calculated to establish the so called sedimentation dynamics curve. In the second one, the methods of suspension image analysis are utilized to determine the positions of the upper dis- continuity and to establish the sedimentation curve. Laboratory research on the sedimentation of agalit particles suspended in glycerine was conducted (using PIV method). Additionally, industrial research on the sedimentation of water-absorbing granular material used after the first carbonation (carbonation I) was conducted in a sugar factory (using the second method). The research consisted of photographic registration of images of the settling suspension by means of the time-lapse photog- raphy technique. A laboratory study was conducted for four values of the volume concentration of agalit particles in glycerine (0.5; 1.0; 1.5 and 2.0 vol%). The research methodology, the scope of the conducted measurements and sample research results together with conclusions are presented in this paper.

11

Investigation of the Sound Source Regions in Open and Closed Organ Pipes

Hruška Viktor, Dlask Pavel

Archives of Acoustics

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2019

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Vol. 44, No. 3

467--474

EN

The airflow in the mouth of an open and closed flue organ pipe of corresponding geometrical proportions is studied. The phase locked particle image velocimetry with subsequent analysis by the biorthogonal decomposition is employed in order to compare the flow mechanisms and related features. The most significant differences lie in the mean velocity distribution and rapidity of the jet lateral motion. Remarks on the pressure estimation from PIV data and its importance for the aeroacoustic source terms are made and a specific example is discussed.

12

Sprawdzenie stosowalności cyfrowej anemometrii obrazowej do badania opływu ruchomych obiektów w przewodzie zamkniętym

Gawor M., Sobczyk J., Wodziak W., Gnatowska R.

Prace Instytutu Mechaniki Górotworu PAN

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2018

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T. 20, nr 3

231--238

PL

Wykonano badania przepływu powietrza wokół poruszającego się obiektu w tunelu aerodynamicznym. Układ pomiarowy składał się z dwóch prętów o przekroju kwadratowym. Pierwszy z prętów został umieszczony na stałe w pobliżu wlotu do komory pomiarowej, natomiast drugi z prętów oddalał się od lub zbliżał do pierwszego z określoną prędkością. Pomiary przy użyciu cyfrowej anemometrii obrazowej przeprowadzono dla prędkości napływu wynoszącej 1.55 m/s oraz prędkości poruszania się pręta 0.01 m/s. Zarejestrowano zmiany struktury przepływu pomiędzy prętami w zależności od odległości między nimi oraz od zwrotu prędkości pręta. Podjęto próbę obiektywnego wyznaczenia odległości pomiędzy prętami przy której następuje zmiana struktury przepływu.

EN

Investigations of airflow past moveable object were carried out in a wind tunnel. Experimental setup consisted of two squares cylinders in the inline configuration. The first of them was permanently attached close to the measuring chamber inlet. The second cylinder was moving forth and back with velocity Vc = 0,01 m/s. Particle Image Velocimetry measurements were performed for the free stream velocity V∞ = 1,55 m/s. Observed flow patterns were changing depending on the distance between cylinders and direction of motion of the cylinder. An attempt was made to objectively determine the distance between cylinders at which the flow patterns used to change.

13

Modele numeryczne turbulencji – źródła i dostosowanie do specyfiki aerologii górniczej

Krawczyk J., Janus J., Głuch B., Skotniczny P., Ostrogórski P.

Prace Instytutu Mechaniki Górotworu PAN

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2018

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T. 20, nr 4

355--362

PL

W artykule omówiono temat modelowania zjawisk turbulentnych w kopalniach podziemnych. Kopalnie podziemne ze względu na technologię wydobycia posiadają skomplikowaną sieć wentylacyjną. Dotychczas stosowane w wentylacji przemysłowej i nie tylko półempiryczne modele turbulencji posiadają stałe, które zostały określone w wyniku badań podstawowych dla geometrii odbiegających od tych spotykanych w górnictwie. Zastosowanie tego typu modeli umożliwia poszukiwanie rozwiązań dla wielu zagadnień, jednak kosztem konieczności sprawdzenia, czy dany model jest w stanie wystarczająco dobrze opisywać wybrane zagadnienia. Dla wentylacji kopalń podziemnych tego typu walidacje przeprowadzono w bardzo ograniczonym zakresie i nie wystarczają one do pełnej reprezentacji zjawisk występujących w wyrobiskach kopalnianych. W związku z tym pojawiła się potrzeba uaktualnienia lub rozszerzenia istniejących wartości stałych stosowanych w modelach numerycznych odpowiednich do geometrii wyrobisk górniczych. W artykule przeprowadzono przegląd dotychczas stosowanej metodyki określania stałych w wybranych modelach turbulencji na podstawie wyników badań eksperymentalnych typowych zagadnień przepływowych. Określono zarys analogicznego programu badań w zakresie wybranych zagadnień przepływowych charakterystycznych dla wentylacji kopalń.

EN

Paper presents discusses about turbulent phenomena modelling in underground mining which, due to the mining technology, has complicated ventilation network. So far, in industrial ventilation semi-empirical turbulence models have been used. These models use constants, which were determined as a result of basic research on geometries of shapes, which in most cases are different from the shapes of workings of underground mines. The use of this type of models helps in searching solutions for many problems, but results of numerical calculations should be checked if the given model is able to describe to selected issues well enough. For underground mine ventilation systems, the validations have been carried out to a very limited extent and they are not sufficient to fully represent phenomena occurring in mine drifts. Therefore, it is necessary to update or extend the existing constants values used in turbulence models to customize them to specific conditions of trhe flow in the workings of underground mines. Paper conatins a review of used methodology for determining constants in selected turbulence models based on results of typical flow problems investigations and an outline of planned studies.

14

Computational fluid dynamics (CFD) numerical simulation and particle image velocimetry (PIV) measurement of a packed flotation column

Yan X., Chen Z., Wang L.

Physicochemical Problems of Mineral Processing

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2018

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Vol. 54, iss. 2

395--405

EN

Packing is a useful method to obtain a static separation environment for a high flotation recovery and selectivity. In this study, the single-phase flow field in a packed lab-scale cyclonic-static microbubble flotation column (FCSMC) was investigated by computational fluid dynamics (CFD) simulation. Turbulence model was verified by Particle Image Velocimetry (PIV) experiment; the simulation results obtained by the RSM (Reynolds Stress Model) are closer to the experimental data. Based on this validation, RSM turbulence model was used to obtain the effect of sieve-plate on the hydrodynamic characteristics in the column flotation zone. The results show that the sieve-plate packing arrangement greatly straightens the rotation flow and decreases the turbulence. To further improve the effect of packing, two layers of sieve plates were used, and one diameter (1D = 190 mm) was selected as the reasonable distance between the two layers of sieve plates. To quantitative evaluate the effect of sieve-plate packing, the logarithm of Pdk over the logarithm of Pdo was calculated based on the volume-averaged turbulence dissipation rate, increasing from 24.72 for one layer of sieve-plate packing to 216.96 for two layers of sieve-plate packing. The probability of detachment significantly decreased for two layers of sieve-plate packing, and the recovery efficiency was significantly improved.

15

Metoda Particle Image Velocimetry (PIV) w aspekcie możliwości zastosowania do badań eksperymentalnych przepływów powietrza w budownictwie energooszczędnym

Szmelter A.

Materiały Budowlane

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2018

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nr 12

53--56

PL

W artykule przedstawiono podstawy metody pomiarowej Particle Image Velocimetry (PIV), stosunkowo nieinwazyjnej techniki wyznaczania pól prędkości płynów. Podjęto próbę nakreślenia stanu badań oraz ich implementacji w Polsce. Opisano możliwości zastosowania metody PIV w różnych dziedzinach nauki i przemysłu, m.in. do badania przepływów powietrza w pomieszczeniach. Zwrócono uwagę na ich wpływ na parametry klimatu wewnętrznego i komfort pomieszczeń. Stwierdzono związek pomiędzy poprawnością i użytkowalnością instalacji wentylacyjnych, klimatyzacyjnych i grzewczych a efektywnością energetyczną budynków. Zawarty w artykule przegląd literatury światowej potwierdza duży potencjał metod PIV w mechanice płynów i związanych z nią gałęziach przemysłu.

EN

The article presents the basics of measuring method Particle Image Velocimetry (PIV), a relatively non-intrusive technique for determining fluid velocity fields. An attempt was made to outline the state of research and implementation of these research in Poland. The possibilities of applying the method in the fields of science and industry are described in examples for the study of indoor airflows were characterized. It was pointed out on their impact on the indoor climate parameters and indoor comfort. A relationship was found between the correctness and usability of ventilation, air conditioning and heating systems and the energy efficiency of buildings. Contained in the article the review of world literature seems to confirm the great potential of PIV methods in fluid mechanics and connected with it branches of industry.

16

Identification of the flow pattern of liquid streams in the shell-side of a segmental-baffled shell-and-tube heat exchanger

Ligus G., Zając D., Kołodziej S.

Journal of Mechanical and Energy Engineering

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2018

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Vol. 2, No 3

245--256

EN

Shell-and-tube heat exchangers are widely used in chemical and process engineering. Assessing hydrodynamics of fluid flow in their shell-side is a highly complex task. This results from the complex geometry of the shell-side itself, defined by such parameters as the tubesheet layout, tube diameter, baffle spacing or baffle cut. Shell-and-tube heat exchangers are the subject of many studies in which design and flow parameters are analysed. However, only a few studies concentrate on issues strictly related to the identification of streams of the liquid flowing in the shell-side of apparatus on an industrial scale. In this article, the authors present the results of an experimental visualization study, utilizing Particle Image Velocimetry (PIV). The experiment used a laser sheet technique along and across a tube bundle. The main results of the measurements and analyses concentrate on identifying the flow pattern of streams in the shell-side and assessing stagnation vortices and their consequences. Finally, detecting bypass streams and leakage streams flowing through design gaps between the shell and the tube bundle as well as between the baffles and the tubes in the bundle are presented.

17

Evaluation of mixture swirl in the cylinder chamber in a conceptual system with combustion surrounded by inactive gases

Cieślik W., Pielecha I.

Combustion Engines

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2018

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R. 57, nr 4

40--47

EN

Internal combustion engines have seen a reduction of the dynamics of their efficiency growth in recent years. All kinds of new modifications and changes introduced in this field can only manage changes of engine efficiency at the level of a fraction of a percent. Considering the concept of unification of SI and CI internal combustion engine structures, one can expect to see their efficiency increase by the reduction of losses, whose causes and occurrence is commonly known. The improvement of the combustion system is mainly related to the reduction of thermal losses generated in this process. Therefore, the current issue is the advanced analysis of any possibilities of improving the combustion conditions and more fully understanding the processes that accompany them. The authors of the article see such a possibility in the conceptual control of the combustion process, which aims to obtain a combustible mixture surrounded by nonflammable gases. This way the flame contact with the cylinder walls is limited, which should in turn contribute to reducing the heat exchange with the walls. This research is a continuation of previous research work; current work focuses on determining the actual distribution of gases in the combustion chamber using the advanced shadow photography method. The article specifies the effect of nonflammable gas injection pressure increase on the area of the boundary layer formed between the non-flammable gases and cylinder walls.

18

The use of liquid crystal thermography TLC and particle image velocimetry PIV in selected technical applications

Stąsiek J. A., Jewartowski M.

Archives of Thermodynamics

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2018

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Vol. 39, no 3

129--147

EN

Nowadays, the energy cost is very high and this problem is carried out to seek techniques for improvement of the aerothermal and thermal (heat flow) systems performances in different technical applications. The transient and steady-state techniques with liquid crystals for the surface temperature and heat transfer coefficient or Nusselt number distribution measurements have been developed. The flow pattern produced by transverse vortex generators (ribs) and other fluid obstacles (e.g. turbine blades) was visualized using liquid crystals (Liquid Crystal Thermography) in combination with the true-colour image processing as well as planar beam of double-impulse laser tailored by a cylindrical lens and oil particles (particle image velocimetry or laser anemometry). Experiments using both research tools were performed at Gdańsk University of Technology, Faculty of Mechanical Engineering. Present work provides selected results obtained during this research.

19

Characteristics of single wood particle pyrolysis using particle image velocimetry

Kluska J., Ronewicz K., Kardaś D.

Archives of Thermodynamics

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2018

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Vol. 39, no 2

3--13

EN

This study examines the pyrolysis of a single cylindrical wood particle using particle image velocimetry (PIV). The pyrolysis was conducted inside a pyrolysis reactor designed for this purpose. The experimental setup presented in this paper is capable of effectively characterizing the intensity of pyrolysis based on velocity distribution in the vicinity of wood particles. The results of the gas velocity distribution show that evaporation of moisture has as a major impact on the formation of the gas cushion as devolatilization.

20

Electrohydrodynamic flow evolution in a narrow wire-plate electrostatic precipitator

Podliński J., Garasz K., Berendt A., Mizeraczyk J.

Przegląd Elektrotechniczny

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2017

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R. 93, nr 2

214--218

EN

In this study, the temporal and spatial evolution of the electrohydrodynamic (EHD) flow for a high voltage positive pulse in a wire-plate electrostatic precipitator (ESP) is investigated, using the Time-Resolved Particle Image Velocimetry (PIV) method. The ESP consisted of a single wire electrode supplied by a positive high voltage and a two grounded plate electrodes. The images recorded just after applying the high voltage as well as velocity field maps of the EHD flow of the dust particles suspended in the air are presented. The results illustrate the temporal and spatial evolution of the EHD flow for different applied voltages and for cases without and with externally forced flow.

PL

W niniejszym artykule przedstawiono wyniki badań rozwoju przepływu elektrohydrodynamicznego (EHD) w elektrofiltrze z jedną drutową elektrodą wyładowczą zasilaną dodatnimi impulsami napięciowymi oraz z dwiema uziemionymi elektrodami płytowymi. Do badań wykorzystano czasowo-rozdzielczą metodę anemometrii obrazowej. Zaprezentowane wyniki ukazują rozwój przepływu EHD dla różnych napięć oraz dla przypadków bez i z wymuszonym przepływem.